Suggested Grounding Scheme

owel · **Posted:** Fri Jul 13, 2007 2:32 pm

I find this grounding scheme very good and acceptable. Noise/RFI/fizz/fuzz/crackle/pop/hum are very minimally heard even at +72dB gain setting.

How it's done:

Basically, both XLR jacks are mounted securely on the metal/aluminum case. Then, pin 1 on each XLR jack (input and output) is also connected to the ground terminal of the XLR jack. Since the metal Neutrik jack is conductive, this also grounds the case.

Both the input and output XLR ground/pin 1 wires are then connected to each other.

Pin 1,2,3 of the XLR jacks are connected to the SC-1 PCB.

You may also lay flat the grounding wire against the back panel and secure it there with a tape.

My test setup:

The outputs of the SC-1 is connected directly to the XLR inputs of a KRK RP-8 monitor so I can hear the noise. Monitor set at normal volume default.

Noise was tested using the scenarios outlined below. This configuration results in the minimal amount of noise for all scenarios listed.

owel · **Posted:** Mon Jul 16, 2007 3:22 pm

Just an addendum:

If your case is conductive (aluminum/steel), and your XLR jack is also conductive, and you have good contact between the XLR jack and the case (test with a multitester for minimum resistance), you can make optional connecting pin 1 of the output xlr to pin 1 of the input xlr.

(But you still need to short pin 1 of xlr to the XLR jack's casing).

corgan4321 · **Joined:** Wed Jun 27, 2007 3:54 pm **Posts:** 70

Would grounding the IEC connector to the XLR ground work to ground the rack?

owel · **Posted:** Tue Nov 27, 2007 6:41 pm

corgan4321 wrote:

Would grounding the IEC connector to the XLR ground work to ground the rack?

The IEC "ground" lug needs to be grounded on the case... this is safety ground. You can use a ring terminal, and attach it to one of the IEC nut and bolt.

Curran · **Joined:** Sun Nov 15, 2009 7:08 pm **Posts:** 16

hey I have the four pre-amps and the rack case bought from your excellent site and i am wondering if i need to perform this grounding scheme to my case as well? or is this for other cases than yours?

owel · **Posted:** Fri Nov 20, 2009 5:07 pm

It's for all cases.

Curran · **Joined:** Sun Nov 15, 2009 7:08 pm **Posts:** 16

so I need too ground between pin1 and the ground lug on the XLR connector AND then from IN to OUT on the preamp XLR's. Do I then need too connect ground between EACH preamp XLR as well? like preamp one to preamp two to preamp three to preamp four?

owel · **Posted:** Fri Nov 20, 2009 5:30 pm

Quote:

so I need too ground between pin1 and the ground lug on the XLR connector

Yes.

Quote:

AND then from IN to OUT on the preamp XLR's.

No need for this one.

Quote:

Do I then need too connect ground between EACH preamp XLR as well? like preamp one to preamp two to preamp three to preamp four?

No need, the XLR case will be making contact with the rack case. So they're all going to be connected together.

Curran · **Joined:** Sun Nov 15, 2009 7:08 pm **Posts:** 16

again you is da man!!!!

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Suggested Grounding Scheme

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